A conventional hand tool can be connected with variety of connection bars or extension bars which includes accommodation recesses so as to be connected with different tool bits. U.S. Pat. Nos. 5,477,434 and 6,183,103 respectively disclose an extension bar with built-in light to be cooperated with hand tools. The built-in light of U.S. Pat. No. 5,477,434 can be activated when a hand tool is connected with the extension bar, and built-in light of U.S. Pat. No. 6,183,103 cannot be activated by the connection of the hand tool, a switch has to be operated to activate the built-in light.
The present invention intends to provide an extension bar with a built-in light which can be activated by either being connected with a hand tool or by operation of a switch member on the extension bar.